Air purity standards which limit emissions into the atmosphere have induced paint manufacturers to develop coating systems with a minimum quantity of organic solvents. One approach toward this end has been the substitution of water for organic solvents and diluents. Metallic aluminum pigments, which are used extensively in organic-based coatings such as decorative automotive top coats, asphaltic roof coatings and metallic maintenance paints, readily react chemically with water to produce hydrogen gas and aluminum hydroxide as indicated by the chemical equation: EQU 2Al+6H.sub.2 O.fwdarw.2Al(OH).sub.3 +3H.sub.2
This reaction not only destroys the unique metallic pigmentation properties of the tiny aluminum mirror-like particles by converting them to a hydrated oxide form unsuitable for pigment use, but it also generates hydrogen gas, which is a fire and explosion hazard.